750177 PNOZ s7.2 24VDC 4 n/o 1 n/c expand PNOZsigma contact expansion, outputs: 4 N/O, 1 N/C, UB 24 V DC, width: 17.5 mm, plug-in screw terminals, contact block for contact expansion in connection with safety-related control components. Mounting further contact blocks to the right is possible.